ACR Y HAD LTSS FROM ACR Z. SYS ERROR.

Narrative

STRONG WINDS FROM SW. WORKING SECTOR 13 RADAR POS ZDV. EVENING RUSH OF ARR ACFT GOING TO DEN STAPLETON ARPT. BLENDED ARRS FROM W; NW; AND N ON J170. SEQUENCE OF RELATED ACFT WERE (IN ORDER) ACR X; ACR Y; ACR Z. ACR X CLRED TO CROSS DRAKE INTXN AT 17000 FT MSL. ACR Y STEPPED DOWN REF ACR X AND ACR Z. ACR X CLRED TO CROSS DRAKE AT 17000 MSL. TO WIDEN THE SPACING BTWN ACFT; ACR Z ASSIGNED HDG OF 200 AND ACR Y ASSIGNED HDG OF 220. ALL ACFT HAD BEEN ASSIGNED 250 KTS PRIOR TO BLENDING. ACR Y (WHEN CLR OF ACR X) WAS ASSIGNED 100 HDG TO INTERCEPT THE DEN 313 DEG RADIAL AND PROCEED INBOUND ON ARR ROUTING. ACR Y ASSIGNED FL190 BUT NOT ENTERED INTO DATA BLOCK. NOTICED LOSS OF SEPARATION AND INSTRUCTED ACR Y TO MAINTAIN (AGAIN) FL190 BECAUSE THE DATA BLOCK REFLECTED ASSIGNED ALT FL200. THIS CAUSED CONFUSION AS TO WHICH ACFT HAD ACTUALLY READ BACK THE CORRECT ASSIGNED ALT. INSTRUCTED ACR Z TO TURN R TO HDG OF 220. CONFLICT ALERT HAD NOT GONE OFF; YET ACFT WERE APPROX 3 NM LATERAL AND 600 FT VERT. CONFLICT DID GO OFF AT 4 NM AND 700 FT. BEING A RELATIVELY INEXPERIENCED CTLR; I SHOULD HAVE NOT BEEN TRYING TO SEQUENCE SO TIGHTLY ALLOWING MYSELF SOME LEEWAY ON SLOW TURNS BY PLTS AND DIFFERENT RATES OF DSCNT.